Roller bearing cage

ABSTRACT

A cage for the rollers in a roller bearing in which the roller axes (2) define an angle with the bearing axis (3) has two annular portions (4, 5) and intermediate cage bars (6) defining cage pockets (7). The bars are situated radially inside of the roller axes with respect to the bearing and a flange (8) for guiding the roller by contacting their ends is extending radially outwards from one of the annular portions (4). A protrusion (9) is arranged on the flange (8) in connection to each pocket (7) or insertion into a recess in the adjacent roller end and thereby keeping the roller in the cage pocket. A recess (10) in the other annular portion (5) opposite each protrusion (9) simplifies the snapping of the roller into its pocket in the cage.

The invention relates to a roller bearing cage of the kind defined inthe introductory clause of claim 1.

A roller cage of pressed sheet metal having stamped roller pockets foruse in spherical roller bearings is known by e.g. U.S. Pat. No.2,218,985. Roller guidance and cage centering take place in such a cageby the rollers contacting the cut rims of the roller pockets. Thiscontact is unsuitable, since the contact surfaces are comparativelysmall, which gives a high contact pressure and poor lubricationconditions and may cause excessive wear.

U.S. Pat. No. 2,375,145 shows that roller guidance can be effected by acage having a flange with a portion contacting an end surface of aroller mounted in the cage. The general structure of such a cage entailscertain disadvantages, however. The radially inwardly directed flangeoccupies the limited space between two adjacent rows of rollers, whichrequires a wider bearing or shorter rollers than necessary. The cagepockets are open at one side, which means, despite the fact that thereis a guiding flange, that the roller guidance is inferior to the rollerguidance in a bearing having a cage with closed roller pockets. The cageand the rollers must be mounted on the inner ring of the bearing bypressing the rollers radially into the respective pockets because theinner ring is provided with flanges. The axial protrusions of the cageare pressed apart by the contact with the envelope surfaces of therollers during mounting. These surfaces are sensitive to defects, sincethey take up the load in the bearing and roll against raceways in theouter and the inner rings. The surfaces can easily be damaged duringmounting by the contact with the protrusions, which are comparativelyhard and rigid.

The object of the present invention is to provide a cage which gives agood roller guidance, requires a small space in the axial direction ofthe bearing and permits careful and safe mounting of the rollers in thecage. This is obtained in a cage of the kind mentioned above by givingit the characterizing features stated in claim 1.

Such a cage can be produced by pressing and stamping of sheet metalblanks, and a bearing comprising such a cage can be quickly and easilyassembled. The cage can be centered in the bearing by its contact withthe rollers and does not have to be equipped with parts which contact abearing ring.

The invention is described in detail in the following with reference tothe accompanying drawing, in which;

FIG. 1 shows an axial section of a portion of a cage according to oneembodiment of the invention;

FIG. 2 shows a view from the outside and radially inward of a portion ofthe outer circumference of the cage, wherein section I--I correspondingto FIG. 1 is indicated;

FIG. 3 shows a portion of the cage according to reference III in FIG. 1;and

FIG. 4 shows an end view of a portion of the cage according to referenceIV in FIG. 1.

The cage here described is suitable for use in a double row sphericalroller bearing. In the section of FIG. 1, a roller 1 for such a bearingis outlined and placed in its proper position in the cage. The axis 2 ofthe roller forms an angle with the central axis 3 of the cage, wherebythe axes or the rollers mounted in the cage define a cone with its apexon the axis 3, which coincides with the axis of the bearing. The cagecomprises two closed annular portions 4, 5 and a number of bars 6 whichextend between the portions 4, 5 and define roller pockets 7. The bars 6extend mainly parallel to the axes 2 of adjacent rollers and aresituated between the axis 3 of the cage and the axes 2 of the rollers.Thereby the bars occupy a minimum of space between the rollers, and thecontact against the envelope surfaces of the rollers has a great radialforce component with respect to the cage, so that the cage is firmlycentered in the bearing by its contact with the rollers.

A flange 8 is arranged at one end of the cage in connection to one ofthe annular portions 4 and extend outwardly from the center of the cage.Thereby it does not significantly limit the space between the rows ofthe rollers in a double row spherical roller bearing. The side surfaceof the flange which is facing the pockets 7 contacts the rollers mountedin the cage on their end surfaces facing the flange. The flange suitablyextends as far radially outwards that the extension of the roller axis 2intersects the flange surface which contacts the rollers, wherebymaximum roller guiding ability is achieved.

Since the cage bars 6 are situated radially inside the roller axes 2with respect to the cage axis 3 and thereby do not limit the radiallyoutward mobility of the rollers, the cage is provided with anarrangement for keeping the rollers in the cage also when they are notenclosed in an outer ring. This arrangement comprises protrusions 9provided on the flange 8 and extending towards the roller pockets andhaving a surface which, in the direction towards the bearing axis,successively increases its distance from the flange surface. Eachprotrusion is situated so as to face the middle of each pocket. Theprotrusion is intended for insertion in a recess in the end surface of aroller situated in the opposing pocket, whereby the wedge shape of theprotrusion allows the roller to be snapped into position in the pocketby pressing the end surface of the roller radially inwards past theprotrusion 9.

This procedure is possible because of the resiliency of the cage. Inorder to ensure that the roller takes the correct position in relationto the pocket and the protrusion 9 during the snap action, recesses 10are provided at the opposite side of the cage in relation to the flange8 in the annular portion 5. The recesses oppose the protrusions 9.Therewith the end portion of each roller can be directed correctly withrespect to the protrusion 9 by being placed in the recess. The existenceof the recess also allows the roller to be axially displaced from theprotrusion 9 in the initial stage of the snapping procedure, whichsimplifies mounting. The envelope surfaces of the rollers are notsubjected to any pressure during the mounting procedure, whichdiminishes the risk for roller damages. A convex edge 11 is suitablyprovided on either side of each recess 10, which edge extends towardsthe interior of the pocket. This arrangement prevents the edges of theroller from contacting the cage when the rollers are tilted, therebydiminishing wear in the bearing.

Also the flange 8 has suitably a convex surface facing the rollers. Thesurface has the shape of a torus in order to give a suitable contactagainst the adjacent roller ends. A flange 12 is preferably arrangedalso in connection to the annular portion 5. Such a flange gives thecage an increased stability and strength. If the flange extendsinwardly, the whole cage may be formed in a simple manner in a pressingand punching tool.

The cage in a double row spherical roller bearing is preferablysupplemented with a loose guide ring 13 (FIG. 1) which encloses theflange 8 of the cages of both rows of rollers. FIG. 1 shows the cage ofone row of rollers only. The guide ring co-operates with the cages inguiding the rollers.

If a roller in the loaded zone in the bearing has a tendency to skew itwill be guided by the contact with the guide ring. At the same time, theguide ring will be displaced toward the loaded zone of the bearing bybeing squeezed into a wedge shaped space between the ends of the rollersof both rows of rollers. Therewith the guide ring displaces the cageradially towards the loaded zone of the bearing due to its contact withthe cage in the unloaded zone so that the play of the rollers in thecage pockets in the loaded zone decreases, whereby the guidance of therollers is further improved.

In high speed bearings, where roller guidance is particularly difficult,the centrifugal force acting on the unloaded rollers will press therollers of the respective rows towards each other, thereby displacingthe guide ring in the direction of the unloaded zone, whereby the axialplay between the roller ends and the guide ring in the loaded zonedecreases. This improves the roller guidance both in the loaded and inthe unloaded zone, which is important in high speeds.

The position of the guide ring on the cage thus makes the guide ringcooperate with the cage in a manner which decreases the possibility ofthe roller to skew during operation.

What is claimed is:
 1. A cage for a row of rollers (1) in a rollerbearing in which the axes (2) of the rollers define a cone, which cagecomprises two closed annular portions (4, 5) and a number of bars (6)extending between said portions, the bars defining roller pockets (7),characterized in that the cage bars (6) extend substantially parallel tothe axes of adjacent rollers and are situated between the bearing axis(3) and the roller axes (2), that a flange (8) is provided at one end ofthe cage in connection to one of said annular portions (4) and extendingradially outwards, the flange having a side surface intended forcontacting the adjacent end surfaces of the rollers situated in thecage, that a number of protrusions (9) extending towards the pockets ofthe cage and having surfaces facing the pockets and successivelyincreasing their distance from the flange surface in the directiontowards the bearing axis are arranged on the flange (8) so as to facethe middle of each pocket (7), respectively, and that the other one ofsaid annular portions (5) is provided with a number of recesses (10)situated opposite the respective protrusions (9).
 2. A roller cageaccording to claim 1, in which the flange surface facing the rollerpockets is convex and torus shaped.
 3. A roller cage according to claim1, in which a convex edge (11) directed towards the pocket is arrangedon either side of each recess in said other annular portion (5).
 4. Aroller cage according to claim 1, in which said other annular portion(5) is provided with an annular flange (12) extending towards thebearing axis.
 5. A roller cage according to claim 1, in which the flange(8) is enclosed by a loose guide ring. .Iadd.6. A cage for a row ofrollers (1) in a roller bearing in which the axes (2) of the rollersdefine a cone, which cage comprises two closed annular portions (4, 5)and a number of bars (6) extending between said portions, the barsdefining roller pockets (7), characterized in that the cage bars (6)extend substantially parallel to the axes of adjacent rollers and aresituated between the bearing axis (3) and the roller axes (2), that aflange (8) is provided at one end of the cage in connection to one ofsaid annular portions (4) and extending radially outward, the flangehaving a side surface intended for contacting the adjacent end surfacesof the rollers situated in the cage, and a number of protrusions (9)extending towards the pockets of the cage and having surfaces facing thepockets. .Iaddend. .Iadd.7. A cage for a row of rollers (1) in a rollerbearing in which the axes (2) of the rollers define a cone, which cagecomprises two closed annular portions (4, 5) and a number of bars (6)extending between said portions, the bars defining roller pockets (7),characterized in that the cage bars (6) extend substantially parallel tothe axes of adjacent rollers and are situated between the bearing axis(3) and the roller axes (2), that a flange (8) is provided at one end ofthe cage in connection to one of said annular portions (4) and extendingradially outward, the flange having a side surface intended forcontacting the adjacent end surfaces of the rollers situated in thecage, and a number of protrusions (9) extending towards the pockets ofthe cage and having surfaces facing the pockets and successivelyincreasing their distance from the flange surface in the directiontowards the bearing axis are arranged on the flange (8) so as to facethe middle of each pocket (7), respectively. .Iaddend. .Iadd.8. A cagefor a row of rollers (1) in a roller bearing in which the axes (2) ofthe rollers define a cone, which cage comprises two closed annularportions (4, 5) and a number of bars (6) extending between saidportions, the bars defining roller pockets (7), characterized in thatthe cage bars (6) extend substantially parallel to the axes of adjacentrollers and are situated between the bearing axis (3) and the rolleraxes (2), that a flange (8) is provided at one end of the cage inconnection to one of said annular portions (4) and extending radiallyoutward, the flange having a side surface intended for contacting theadjacent end surfaces of the rollers situated in the cage, and a numberof protrusions (9) extending towards the pockets of the cage and havingsurfaces facing the pockets, and that the other one of said annularportions ( 5) is provided with a number of recesses (10) situatedopposite the respective protrusions (9). .Iaddend.